Determining the 'unit cost balance point' for an air source heat
Is this calculation/formula correct for determining the 'unit cost balance point' of an air source heat pump vs a gas furnace for my particular situation (electricity unit cost of $0.162 / KWh and gas unit cost of $1.3463 / Therm and an 80 AFUE furnace efficiency)?
KWh / $0.162 x COP[unit cost point] x Therm / 29.3 KWh = Therm / $1.3463 x 0.80
COP[unit cost point] = 0.162 / 1.3463 x 29.3 x 0.80 = 2.82
Therefore, for my particular situation, is an air source heat pump more economical on a unit cost basis, if it can deliver greater than 2.82 COP at a given temperature?